Orthopaedic implant with porous structural member

ABSTRACT

A tool for use with an orthopaedic implant includes: a tubular assembly including a tubular passage having a first end and a second end, the first end including a means for attachment to an implant body; a plug; and a plunger coupled to the plug. The tubular passage is configured to receive, via the second end, a material agent and the plunger coupled to the plug. The plunger is configured to slide through the tubular passage for expelling the material agent from the tubular passage into a load bearing member via the at least one first opening. The plunger is configured to rotate within the tubular passage for coupling the plug with the first opening to seal the first opening against expulsion of the material agent from the load bearing member via the first opening.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a division of U.S. patent application Ser. No. 15/878,723entitled “ORTHOPAEDIC IMPLANT WITH POROUS STRUCTURAL MEMBER,” filed Jan.24, 2018, which is incorporated herein by reference. U.S. patentapplication Ser. No. 15/878,723 is a continuation-in-part applicationbased on U.S. patent application Ser. No. 15/626,596 entitled“ORTHOPAEDIC IMPLANT WITH POROUS STRUCTURAL MEMBER,” filed Jun. 19,2017, which is incorporated herein by reference. U.S. patent applicationSer. No. 15/626,596 is a division of U.S. patent application Ser. No.14/637,142 entitled “ORTHOPAEDIC IMPLANT WITH POROUS STRUCTURAL MEMBER”,filed Mar. 3, 2015, which has now issued as U.S. Pat. No. 9,700,431 andwhich is incorporated herein by reference. U.S. patent application Ser.No. 14/637,142 is a continuation-in-part application based upon U.S.patent application Ser. No. 12/540,515, entitled “ORTHOPAEDIC IMPLANTWITH POROUS STRUCTURAL MEMBER”, filed Aug. 13, 2009, which isincorporated herein by reference. U.S. patent application Ser. No.12/540,515 is based upon U.S. provisional patent application Ser. No.61/088,460, entitled “SPINAL DEVICES”, filed Aug. 13, 2008, which isincorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to orthopaedic devices, and, moreparticularly, to orthopaedic implants.

2. Description of the Related Art

Most orthopaedic implants are formed from a metallic material suitablefor a given implant, such as a hip implant, knee implant, glenoidimplant, etc. In the case of articulating joints, the implant mayinclude a non-metallic load bearing surface, such as an ultra highmolecular weight polyethylene (UHMWPE). The UHMWPE is attached to themetallic body of the implant, and provides the implant with good wearcharacteristics and low friction.

It is also known to provide an implant with a porous bony ingrowthsurface. For example, a hip implant may include a porous surface on thestem which is intended to allow bony ingrowth of the proximal end of thefemur bone. Such a porous surface may be in the form of a metal poroussurface which is bonded, such as by heat sintering, to the stem of theimplant. Examples of porous surfaces of this type include a woven mesh,a fiber mesh and particles. Knee implants are also known that includeporous ingrowth surfaces that can bear load from surrounding anatomicstructures.

Porous surfaces of the type described above which are used with implantsare not typically part of a single structural member with two opposed,external porous surfaces. For example, in a knee implant, the distalsurface of the implant can sit on the porous material that is slightlyabove the substrate material, but the porous material only typically hasone external surface for tissue ingrowth. For hip implants, the porousingrowth surface is usually provided as a coating on a structuralcomponent of the implant, such as the stem.

In some orthopaedic applications, such as spinal cages, it is beneficialto have a porous member that extends between two external, load bearingsurfaces of the implant. In such arrangements, a cavity is typicallyformed between the two external surfaces of the implant and filled witha porous ingrowth material, which is typically a natural substance suchas cancellous bone tissue. Such an implant is described in U.S. PatentApplication No. 2002/0091447 to Shimp et al. One problem with theimplant described by Shimp et al. is that harvesting sufficientcancellous bone tissue to fill the cavity is expensive, and hostrejection issues can be a concern. Other similar implants thatcontemplate utilizing natural or synthetic materials are described inU.S. Patent Application Publication No. 2004/0210316 to King et al., andU.S. Pat. No. 6,423,095 to Van Hoeck et al. In each of these describedimplants, the porous material held in the cavity is fairly isolated frombearing load from surrounding anatomic structures after implantation,with external surfaces that are either flush or below the mostprotruding external surface of the main implant body. This isintentional, as the materials placed in the cavity tend to havesignificantly lower strength than the implant body. However, isolatingthe porous ingrowth material from bearing loads from surroundinganatomic structures also decreases the amount of surface area the porousingrowth material has in contact with the anatomic structures, which canslow down integration of the implant. In addition, the porous materialsplaced in the cavity are typically resorbable by the body and will notlast throughout the life of the implant.

Porous materials in a cavity of an implant may be loaded with one ormore types of biological agents, to assist with the healing of nearbyanatomical structures or tissues, or to protect against infections, orto fight disease, via the absorption of the agent by the surroundingtissue via the pores of the porous material. However, problems existwith expulsion of the agent from the pores after loading the porousmaterial with the agent and prior to implantation of the implant, and ofleakage of the agent through the opening via which the implant wasinitially loaded, particularly if the agent was loaded into the implantafter the implant was positioned in the body.

What is needed in the art is an orthopaedic implant and associateddevices and methods that can overcome some of the disadvantages of knownimplants and methods.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, there is provideda tool configured for use with an orthopaedic implant. The orthopaedicimplant includes an implant body having a first surface, a secondsurface opposite the first surface, a cavity formed therein that extendsthrough the first surface and the second surface, the implant body beingsubstantially non-porous and further including a third surface with atleast one first opening formed therethrough to the cavity and at leastone second opening, the at least one first opening comprising anthreaded outer portion having an outer diameter and an threaded innerportion having an inner diameter, the outer diameter greater than theinner diameter. The implant further includes a load bearing memberincluding a substantially porous material held within the cavity, theload bearing member configured to receive, via the at least one firstopening, a material agent, the load bearing member having a firstcontact surface extending out of the cavity past the first surface. Thetool includes a tubular assembly having a tubular passage including afirst end and a second end, the first end having a means for attachmentto the implant body, a plug, and a plunger coupled to the plug. Thetubular passage is configured to receive, via the second end, thematerial agent and the plunger coupled to the plug. The plunger coupledto the plug is configured to slide through the tubular passage forexpelling the material agent from the tubular passage into the loadbearing member via the at least one first opening. The plunger coupledto the plug is also configured to rotate within the tubular passage forcoupling the plug with the first opening to seal the first openingagainst expulsion of the material agent from the load bearing member viathe first opening.

In accordance with an aspect of the present invention, there is provideda method of charging an orthopaedic implant with a material agent. Theorthopaedic implant includes an implant body having a first surface, asecond surface opposite the first surface, a cavity formed therein thatextends through the first surface and the second surface, the implantbody being substantially non-porous and further including a thirdsurface with at least one first opening formed therethrough to thecavity and at least one second opening, the at least one first openingcomprising an threaded outer portion having an outer diameter and anthreaded inner portion having an inner diameter, the outer diametergreater than the inner diameter. The implant further includes a loadbearing member including a substantially porous material held within thecavity, the load bearing member configured to receive, via the at leastone first opening, a material agent, the load bearing member having afirst contact surface extending out of the cavity past the firstsurface. The method includes coupling a tubular assembly to the thirdsurface of the implant body, wherein the tubular assembly includes atubular passage having a first end and a second end, and wherein thefirst end is coupled to the third surface such that said tubular passageis centered on the at least one first opening, placing the materialagent into the tubular passage via the second end, sliding a plungercoupled to a plug through the tubular passage via the second end,thereby expelling the material agent from the tubular passage into theload bearing member via the at least one first opening, and rotating theplunger within the tubular passage for coupling the plug with the atleast one first opening for sealing the at least one first openingagainst expulsion of the material agent from the load bearing member viathe first opening.

An advantage of the present invention is that the orthopaedic implantcan be initially charged with a material agent before or after theimplant is placed in the body, or re-charged with the material agentduring a second surgical procedure.

Another advantage of the present invention is that one or more openingsof the orthopaedic implant, through which the implant is charged withthe material agent, can be sealed against leakage or expulsion of thematerial agent from the implant.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a perspective view of an embodiment of a solid component of adevice formed according to the present invention;

FIG. 2 is a perspective view of an embodiment of a porous component of adevice formed according to the present invention;

FIG. 3 is a perspective view of a device created from the solidcomponent shown in FIG. 1 and the porous component shown in FIG. 2;

FIG. 4 is a cross-sectional view of a single, continuous layer withporous and solid regions;

FIG. 5 is a perspective view of an embodiment of a spinal cage withwindows;

FIG. 6 is a cross-sectional view of the spinal cage shown in FIG. 5taken along line 6-6;

FIG. 7 is a perspective view of an embodiment of a spinal cage with aledge or groove;

FIG. 8 is a cross-sectional view of the spinal cage shown in FIG. 7taken along line 8-8;

FIG. 9 is a perspective view of an embodiment of a spinal cage with atwo-part solid component that is assembled to contain the porousmaterial;

FIG. 10 is a cross-sectional view of the spinal cage shown in FIG. 9taken along line 10-10;

FIG. 11 is a perspective view of an embodiment of a spinal cage withlaminates perpendicular to an axis of the spinal cage;

FIG. 12 is a perspective view of an embodiment of a spinal cage withlaminates parallel to an axis of the spinal cage;

FIG. 13 is a perspective view of an embodiment of a spinal cage withlaminates at an angle to an axis of the spinal cage;

FIG. 14 is a perspective view of an embodiment of a spinal cage;

FIG. 15 is a perspective view of another embodiment of a spinal cage;

FIG. 16 is a perspective view of yet another embodiment of a spinalcage;

FIG. 17 is a perspective view of yet another embodiment of a spinalcage;

FIG. 18 is a sectional view of an implant with features for the deliveryof therapeutic agents;

FIG. 19 is a sectional view of a tapered implant;

FIG. 20 is a sectional view of another tapered implant;

FIG. 21 is a sectional view of yet another tapered implant;

FIG. 22 is a sectional view of yet another tapered implant;

FIG. 23 is a sectional view of yet another tapered implant;

FIG. 24 is a perspective view of an implant showing teeth that mate withsurrounding bone;

FIG. 25 is a side view of the implant shown in FIG. 24;

FIG. 26 is a spinal fusion device;

FIG. 27 is a perspective view of another embodiment of an orthopaedicimplant according to the present invention;

FIG. 28 is a side view of the orthopaedic implant shown in FIG. 27;

FIG. 29 is a front view of the orthopaedic implant shown in FIGS. 27-28;

FIG. 30 is a perspective view of yet another embodiment of anorthopaedic implant according to the present invention;

FIG. 31 is a side view of the orthopaedic implant shown in FIG. 30;

FIG. 32 is a perspective view of yet another embodiment of anorthopaedic implant according to the present invention;

FIG. 33 is a front view of the orthopaedic implant shown in FIG. 32;

FIG. 34 is a side view of the orthopaedic implant shown in FIGS. 32-33;

FIG. 35 is a side view of the orthopaedic implant shown in FIGS. 32-34including an ingrowth material;

FIG. 36 is a perspective view of yet another embodiment of anorthopaedic implant according to the present invention;

FIG. 37 is a side view of the orthopaedic implant shown in FIG. 36;

FIG. 38 is a side view of the orthopaedic implant shown in FIGS. 36-37including an ingrowth material;

FIG. 39 is a perspective view of an orthopaedic implant according to thepresent invention;

FIG. 40 is a side view of the orthopaedic implant of FIG. 39, accordingto an embodiment of the present invention;

FIG. 41 is a cross-sectional view of the orthopaedic implant of FIG. 39,with the plug removed, according to an embodiment of the presentinvention;

FIG. 42 is a top view of the plug of the orthopaedic implant of FIG. 39,according to an embodiment of the present invention;

FIG. 43 is a cross-sectional view of the orthopaedic implant of FIG. 39,including the plug 532, coupled to the first opening for sealing thefirst opening, according to an embodiment of the present invention;

FIG. 44 illustrates a cross-sectional view of an insertion/delivery (ID)tool coupled to the orthopaedic implant of FIG. 39, according to anembodiment of the present invention;

FIG. 45 is a perspective view of the components of the ID tool of FIG.44, according to an embodiment of the present invention;

FIG. 46 is a top view of the first end of the plunger of the ID tool,according to one embodiment of the present invention; and

FIG. 47 are method steps for charging of the orthopaedic implant of FIG.39 with a material agent.

The exemplifications set out herein illustrate embodiments of theinvention, and such exemplifications are not to be construed as limitingthe scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

I. Porous Spinal Devices—Laminate Designs

The present invention provides a laminate method for a spinal implant orimplant component, including manufacturing methods for sheet creation,bonding/assembly methods, and ways of creating tapers. Further, thepresent invention provides delivery of therapeutic agents through aspinal device.

The present invention addresses these issues by providing the design andmethod of manufacturing of a porous spinal fusion device.

A. Materials

Material options for the spinal device include the following:implantable polymers (such as PEEK, PMMA), implantable reinforcedpolymers (such as carbon-fiber reinforced PEEK), implantable metals(such as titanium, titanium alloy), and implantable ceramics (such ashydroxyapatite, alumina). One or more of these materials can be combinedin a given device.

B. Overall Design

With regard to the overall design, the implant can include entirelyporous material or one or more porous regions and one or more solidregions. Additionally, an entirely porous device can be created to matewith existing solid devices (See FIGS. 1-3).

The porous region is created by stacking layers of material withinterconnecting holes/geometry (hereafter referred to as holes).

The solid region can be formed by traditional techniques such asinjection molding or machining or by bonding solid sheets together. Thelater method allows the solid and porous regions to be created fromcontinuous sheets (See FIG. 4).

The holes in the sheets can be created by, for example, laser cutting,punching, etching, electrical discharge machining, plasma etching,electroforming, electron beam machining, water jet cutting, stamping, ormachining. For polymer based materials, they can be created as thesheets are created by, for example, extruding, injection molding, or hotstamping.

Attachment of the sheets to each other can be achieved by any number ofways, including the following:

1. Heat. Heat can be generated by several ways:

-   -   a. Ultrasonic welding—use ultrasonic waves to create heat at the        interface of layers.    -   b. Heat staking—use a heated tool to cause melting between the        layers    -   c. Vibratory welding    -   d. Laser welding    -   e. Convection—use an oven to create heat to cause bonding    -   f. Intermediary layer—for example, use a material that can        absorb energy waves that pass through the polymer (for example        PEEK) without causing damage. The absorbed energy will cause        localized heating. An example of such a coating is Clearweld by        Gentex® Corporation. The laser waves that Clearweld absorbs pass        through the PEEK without causing damage, allowing the layers to        be melted together without large scale damage to the PEEK.

2. Chemical.

-   -   a. Adhesives—a secondary material (such as adhesive) can be used        to bond the material.    -   b. Solvent bonding—a material in which the polymer or reinforced        polymer is soluble can be applied to the sheet surfaces allowing        multiple surfaces to be bonded to one another.    -   c. Overmolding—overmolding of the polymer or reinforced polymer        can provide a chemical bonding

3. Mechanical.

-   -   a. Overmolding—overmolding of a polymer or reinforced polymer        can create a mechanical lock between components on a micro or        macro scale (microscale—the molded material locks with surface        asperities of the existing material. Macroscale—features such as        tongue-groove connections or undercuts). The overmolded material        can be a separate component from the layers or one layer can be        overmolded onto another layer.    -   b. Features are provided within the layers or by a separate        component which provides a mechanical lock—e.g. A pin, snap lock        connection, dove-tail, tongue-groove, rivet, screw and/or        melting tabs to create a mechanical lock. For example, one or        more rivets can connect all layers of a porous implant together.        These connection features can be made of any implantable        material including, but not limited to, titanium, titanium        alloy, PEEK, and/or other implantable polymers. These features        can also be used as radiopaque markers as is described below.    -   c. Some adhesives provide a mechanical bond in addition to or        instead of a chemical bond.

4. Combinations of any/all of the above methods.

If the porous and solid regions are created separately (as in FIGS.1-3), it may be desirable to bond the two together. There are severalmethods of achieving this bond:

1. Heat. Heat can be generated by several ways:

-   -   a. Ultrasonic welding—use ultrasonic waves to create heat at the        interface of layers.    -   b. Heat staking—use a heated tool to cause melting between the        layers    -   c. Vibratory welding    -   d. Laser welding    -   e. Convection—use an oven to create heat to cause bonding    -   f. Intermediary layer—for example, use a material that can        absorb energy waves that pass through the polymer (for example        PEEK) without causing damage. The absorbed energy will cause        localized heating. An example of such a coating is Clearweld by        Gentex® Corporation. The laser waves that Clearweld absorbs pass        through the PEEK without causing damage, allowing the layers to        be melted together without large scale damage to the PEEK.

2. Chemical.

-   -   a. Adhesives—a secondary material (such as adhesive) can be used        to bond the material.    -   b. Solvent bonding—a material in which the polymer or reinforced        polymer is soluble can be applied to the sheet surfaces allowing        multiple surfaces to be bonded to one another.    -   c. Overmolding—overmolding of the polymer or reinforced polymer        can provide a chemical bonding

3. Mechanical.

-   -   a. Overmolding—overmolding of a polymer or reinforced polymer        can create a mechanical lock between components on a micro or        macro scale (microscale—the molded material locks with surface        asperities of the existing material. Macroscale—features such as        tongue-groove connections or undercuts). The overmolded material        can be a separate component from the layers or one layer can be        overmolded onto another layer.    -   b. Features are provided within the layers or by a separate        component which provides a mechanical lock—e.g. A pin, snap lock        connection, dove-tail, tongue-groove, rivet, and/or melting tabs        to create a mechanical lock. For example, the porous material        can attach to the windows that are typical in spinal cages or to        a groove or ledge is created along the interior edge of the        solid ring (see FIGS. 5-10). These connection features can be        made of any implantable material including, but not limited to,        titanium, titanium alloy, PEEK, and/or other implantable        polymers. These features can also be used as radiopaque markers        as is discussed later in this disclosure.    -   c. Some adhesives provide a mechanical bond in addition to or        instead of a chemical bond.

4. Combinations of any/all of the above methods.

Assembly of layer to layer or one component to another (for example aporous component to a solid component) can be aided by such ways assurface modifications to improve adhesive or solvent bonding orroughened surfaces.

FIGS. 5-6 illustrate a spinal cage showing windows (a cross section viewis shown at the right). This is an example of a type of feature ontowhich the porous component can be bonded.

FIGS. 7-8 illustrate a spinal cage showing a ledge or groove (a crosssection view is shown at the right). This is an example of a type offeature onto which the porous component can be bonded.

FIGS. 9-10 illustrate a spinal cage showing a two-part solid componentthat is assembled to contain the porous material. In this examplemechanical means (screw/rivet) are used in conjunction with an adhesivebond. Adhesive ways alone, mechanical ways alone or any of the othermanufacturing methods discussed in this disclosure are also options.

FIGS. 11-13 illustrate a spinal cages showing laminates perpendicular,parallel, and at an angle to the axis of the implant.

The laminate portion of the implant can have layers oriented in anydirection. For example, the layers can be perpendicular, parallel, or atan angle to the axis of the implant (See FIGS. 11-13). This angle neednot be constant within an implant.

The overall shape of the implant can be of any typical existing type,such as ALIF, TLIF, PLIF, and standard round cages (see FIGS. 14-17)

C. Delivery of Therapeutic Agent.

This device can be used to deliver therapeutic agents directly to thetissue surrounding the implant (See FIG. 18). Some examples ofsituations in which this would be desired: delivery of oncologytreatments to cancerous tissue or tissue surrounding cancerous tissue;delivery of agents (such as BMP, hydroxyapatite slurry, and/orplatelets) to encourage/enhance bone growth to promote faster and betterfusion; and delivery of analgesic agents to reduce pain. This list isnot exhaustive.

FIG. 18 illustrates a sectioned, side-view of an implant with featuresfor the delivery of therapeutic agents.

The implant can include a reservoir for delivery of the therapeuticagent over an extended period of time. Openings leading from thereservoir to the porous material allow for controlled release of thetherapeutic agents at a desired rate. The reservoir can be refilled atany time before, during, or after the surgery.

If immediate delivery of the therapeutic agents to the surroundingtissue is all that is required (not extended time release), the designneed not include a reservoir. In this case, the therapeutic agents canbe directly routed from the implant access to the porous material viachannels. However, a reservoir can be included in an immediate deliverydesign; the openings in the reservoir would be sized to allow forimmediate release of the therapeutic agent rather than a slower,long-term delivery.

The access in the implant (see FIG. 18) can mate with an insertion of adelivery tool (such as a needle) or a device (or catheter leading to adevice) to allow for remote filling of the reservoir (such as by way ofa subcutaneous port or external pain-pump).

In order to allow and promote bone growth through the implant from onevertebra to the other, openings run from the superior to the inferiorportion of the implant and be appropriately sized to allow for boneingrowth (See FIG. 18).

D. Anterior-Posterior Taper

Some implants are tapered to mate with the natural anterior-posteriortaper that exists between vertebrae. If a solid portion exists, thistaper can be created by traditional machining and/or molding techniques.In the porous region, there are several ways of creating this taper,including the following:

-   -   a. If the design includes a reservoir, the reservoir itself can        be tapered. The porous ingrowth layers can be of uniform        thickness and layered outside of the reservoir (as indicated in        FIG. 18).    -   b. A wedge-shaped piece or pieces can create the taper with the        ingrowth layers stacked on the wedge(s). This is essentially the        same design as shown in FIG. 20 without the reservoir, access        and holes for the therapeutic agent delivery. To allow and        promote bone growth through the implant from one vertebra to the        other, openings run from the superior to the inferior portion of        the implant and be appropriately sized to allow for bone        ingrowth (See FIG. 18).    -   c. Shorter layers can be stacked with larger layers to create an        overall taper as in FIG. 19.    -   d. Layers of varying lengths can be sacked to create a stepped        taper as in FIG. 20.    -   e. Similar to the technique in (d), layers of varying length can        be stacked. A smooth taper can be created by using layers that        are tapered prior to stacking or the smooth taper can be        created, by such ways as machining or hot forming, after the        layers are stacked. The second of these would involve first        creating a part like that in (d), then removing material to        create the smooth taper shown in FIG. 21.    -   f. Another way of creating a smooth surface on a stepped taper        is to have one or more outer layers which are parallel to the        taper face, as shown in FIG. 22.    -   g. The design in (f) does not allow for a large amount of        contact area between the outer layer of the taper and the        corners of the stepped layer. One way of providing increased        contact area (which can provide increased strength) is to taper        the stepped layers as in FIG. 21 before adding the outer        layer(s) that are parallel to the face of the taper. An example        of this is shown in FIG. 23.        E. Interface with Bone

It is often desirable to have an implant-bone interface with relativehigh friction. Traditionally, this is achieved by such ways as aroughened implant surface, teeth (See FIGS. 24-25), spikes, or hooks.

In a laminate implant, there are several options for creating suchfeatures. These options include the following:

-   -   a. Form features prior to bonding laminate sheets: Form teeth or        other “rough” features into the outermost layers of the implant        prior to bonding them to the other sheets. These teeth can be        created by several ways:        -   i. Form material—for example: heat forming, cold forming.        -   ii. Remove material—for example: machining, laser cutting,            chemical etching.        -   iii. Add material—attach material to create the features by,            for example, insert molding, mechanical attachment, adhesive            bonding, laser welding, solvent bonding.    -   b. Form features after bonding laminate sheets: Form the rough        surface features on the faces of the implant after the sheets        have been bonded. These features can be formed by the same ways        as listed in (a).    -   c. Secondary feature (such as hooks, spikes, etc) protruding        from the implant into the bone. This feature can be attached by,        for example, insert molding, mechanical attachment, adhesive        bonding, laser welding, or solvent bonding.

FIGS. 24-25 illustrate an implant showing teeth that mate with thesurrounding bone.

F. Interface with Instruments

To aid in insertion of the implant into position in the body, it isoften necessary to attach the implant to instrumentation. The materialnear the interface of the instrument and implant can often seeadditional stress. In a partially or fully laminate implant, it may benecessary to provide additional support in the region of this interface.This can be achieved by a number of ways, including: designing theinstrument to reduce stresses and/or strengthening the implant in theregion of the interface. For example, in the case of an instrument thatcontains a male thread which mates with a female thread in the implant,the implant can be strengthened by adding metal, solid polymer, orreinforced polymer in the region of the female thread. In machinedesign, thread inserts are frequently used to repair damaged threads. Inthis case, thread inserts can be used to strengthen the implant at theinterface with the instrument(s).

G. Radiopaque Markers

When a radiolucent material, such as unfilled PEEK, is used, it issometimes desirable to have the ability to see some or all of thatimplant on a diagnostic tool such as x-ray without the white-outproblems of solid metal. For example, the surgeon may use such markersto determine the orientation and position of the implant to ensureproper placement during surgery. Radiopaque markers can provide thisability. The opacity and/or amount of radiopaque material can becontrolled so that the marker does not prevent evaluation of the tissuenear the implant by x-ray or other diagnostic ways. Material optionsinclude, but are not limited to, the following:

-   -   a. Implantable metals (stainless steel, titanium, or titanium        alloys for example).    -   b. Barium sulfate filled PEEK.    -   c. Carbon filled PEEK.    -   d. Other polymers with radiopaque material (such as barium        sulfate or zirconium dioxide).

Examples of the marker design include one or more of the following:

-   -   a. One or more radiopaque pins.    -   b. Assembly features such as rivets or pins.    -   c. Coating a portion of the device with a radiopaque material.        Examples of methods for creating a radiopaque coating include,        but are not limited to, the following:        -   i. Using chemical vapor deposition to deposit a layer of            titanium onto the polymer.        -   ii. Using a radiopaque ink such as Radiopaque™ ink            (developed by CI Medical).    -   d. One or more of the laminate layers being radiopaque. Examples        of methods to make the layer(s) radiopaque include, but are not        limited to, the following:        -   i. Making the layer from an implantable metal (such as            tantalum, titanium, titanium alloy, cobalt chrome, or            stainless steel).        -   ii. Using a barium sulfate filled polymer to create the            layer.        -   iii. Coating the layer with a radiopaque material—for            example, using chemical vapor deposition to deposit a layer            of titanium onto the surface of one or more layers.    -   e. A slightly radiopaque porous material. This can be achieved,        for example, by using a polymer with barium sulfate.        II. Porous Polymer Spinal Fusion Devices

The key to the success of a spinal fusion surgery is the formation ofgood bone growth between the vertebrae that are being fused. Evaluationof this bone growth is, thus, critical to determining the progress andeventual success of the surgery.

Existing porous spinal cages are made of biocompatible metals. Due tothe density of these metals, the implants made post-operativeexamination of the tissue surrounding the implant difficult.

Several current devices are now made from solid biocompatible polymerssuch as PEEK. PEEK is a relatively radiolucent material. While thisaddresses the issue of radiopacity for solid fusion devices, it is oftendesired to encourage more rapid bone growth between the two vertebrae.

One solution for this problem is implants made from porous biocompatiblepolymers, such as PEEK or reinforced porous PEEK.

A. Overall Design

Such implants can be entirely porous or have a mix of porous and solidpolymer. For example, a solid ring of material can surround a porouscore (See FIG. 26).

FIG. 26 illustrates a spinal fusion device with solid region (Region 1)and porous region (Region 2)

One embodiment of the design is a porous center component that mateswith existing solid, ring-like devices. This device could be assembledwith the solid device in a manufacturing setting or in the operatingroom.

If a solid region/component exists, the porous and solid regions mayneed, but do not necessarily need, to be attached to one another.Examples of methods that can be used to attach the porous and solidmaterial are:

-   -   a. Mechanical features—snap-fit connections, ‘dove-tail’ types        of connections.    -   b. Adhesive bonding.    -   c. Solvent bonding.    -   d. Heat applied by, for example, laser, ultrasonic or vibratory        welding, convection heating, heat staking.        B. Material    -   a. Method of creating porosity        -   i. Laminate design—bonding sheets of material which contain            holes.        -   ii. Foaming methods.        -   iii. Bond ‘beads’ of polymer—bead of any shape can be bonded            together (via, for example, heating, adhesive bonding, or            solvent bonding) to create a porous structure.        -   iv. Mix of polymer and dissolvable material.            -   1. One method involves creating a mixture of powdered                implantable material (e.g. PEEK) and a powder (e.g.                salt) that is soluble in something in which the                implantable material is not soluble (such as water,                isopropyl alcohol for the PEEK example). The mixture is                then heated to bond the implantable particles together.                Pressure can also be applied to aid in the bonding of                particle to particle. Heat can be created by convection                or other ways (such as coating the powder with a                material that absorbs a given range of energy waves—such                as laser waves—and causes heating. E.g. Clearweld                coating by Gentex® Corporation). Finally, dissolve away                the filler to create the porous implantable material.                This method can create net shape parts or raw material                shapes from which individual parts can be created.            -   2. Another method involves mixing an implantable polymer                with a dissolvable material such as described above. The                mixture is then pelletized and then injection molded to                an intermediary or the final part shape. The filler is                dissolved away to create the porous implantable polymer.    -   b. Reinforcement—If improved mechanical properties are desired,        various reinforcing materials can be used. For example, carbon        fiber or barium sulfate can be used.        C. Radiopaque Markers

It is sometimes desirable to have the ability to see some of the implanton a diagnostic tool such as an x-ray without the white-out problems ofsolid metal. For example, the surgeon may use such markers to determinethe orientation and position of the implant to ensure proper placementduring surgery. Radiopaque markers can provide this ability. The opacityand/or amount of radiopaque material can be controlled so that themarker does not prevent evaluation of the tissue near the implant byx-ray or other diagnostic ways. Material options include, but are notlimited to, the following:

-   -   a. Implantable metals (stainless steel, titanium, or titanium        alloys for example).    -   b. Barium sulfate filled PEEK.    -   c. Carbon filled PEEK.    -   d. Other polymers with radiopaque material (such as barium        sulfate or zirconium dioxide).        Examples of the marker design include one or more of the        following:    -   a. One or more radiopaque pins.    -   b. Coating a portion of the device with a radiopaque material.        Examples of methods for creating a radiopaque coating include,        but are not limited to, the following:        -   i. Using chemical vapor deposition to deposit a layer of            titanium onto the polymer.        -   ii. Using a radiopaque ink such as Radiopaque™ ink            (developed by CI Medical).    -   c. A slightly radiopaque porous material. This can be achieved,        for example, by using a polymer with barium sulfate.

Referring now to FIGS. 27-29, an embodiment of an orthopaedic implant100 according to the present invention is shown that includes an implantbody 102 formed from a substantially non-porous material having a firstsurface 104 and a second surface 106 opposite the first surface 104. Asused herein, “substantially non-porous” indicates a porosity of 5% orless, so that the implant body 102 is mostly solid. The implant body 102can be formed from a variety of different materials that arebiocompatible and commonly used to form orthopaedic implants, includingpolyether ether ketone (PEEK), other polyaryl ether ketones (PAEKs),titanium, stainless steel, cobalt chrome, ultra-high molecular weightpolyethylene (UHMWPE), or any previously described material. It shouldbe appreciated that these materials are exemplary only and otherbiocompatible materials could be used to form the implant body. As shownin FIGS. 27-29, the implant body 102 is formed in the shape of acervical cage for spinal applications, but other shapes can also beused, as shown further herein. The first surface 104 and second surface106 can be curved, as shown, or can be formed as planar surfaces thatare substantially flat. Alternatively, one of the surfaces 104, 106 canbe formed as a surface with one or more curvatures while the othersurface is planar.

A cavity 108 is formed in the implant body 102 extending through thefirst surface 104 and second surface 106 to form a continuous cavity 108through the implant body 102. The cavity 108 has a first cavity entrance110 formed through the first surface 104 and a second cavity entrance112 (shown in FIG. 28) formed through the second surface 106. One orboth of the cavity entrances 110, 112 can be concentrically formedthrough their respective surface 104, 106 so that the cavity entrances110, 112 have a perimeter shape that approximately matches a perimetershape of their respective surface 104, 106, with the cavity entrances110, 112 having a smaller perimeter than their respective surfaces 104,106. The cavity 108 can be formed to have a constant or varying shapethroughout.

A load bearing member 114 comprising a substantially porous materialhaving a first contact surface 116 is held within the cavity 108 that isformed within the implant body 102. As used herein, “substantiallyporous” indicates a porosity of at least 20%, but can be significantlyhigher. For example, the load bearing member 114 can have a totalvolume, that is the entire volume occupied by the load bearing member114, of which 60% or more is defined by pores 117 formed in the loadbearing member 114. In other words, 40% of the total volume of the loadbearing member 114 can be occupied by structural material forming theload bearing member 114 while 60% of the total volume is occupied byempty spaced defined by the pores 117, in aggregate. If an extremelyporous material is used to form the load bearing member 114, the pores117, in aggregate, can occupy 80% or more of the total volume of theload bearing member 114. If desired, one or more therapeutic agents canbe held within some or all of the pores 117 for elution into surroundinganatomic features after implantation of the orthopaedic implant 100 toincrease the efficacy of the surgical procedure. A non-exhaustive listof possible therapeutic agents that can be provided in the pores 117includes various growth factors, bone morphogenetic factors, bonemorphogenetic proteins, anti-microbial agents, anti-inflammatories,anti-coagulants, painkillers, cytotoxic substances, stem cells, and anyother substance, known or unknown, that is desirable to elute from theorthopaedic implant 100 following implantation. The material(s) used toform the load bearing member 114 should, like the implant body 102, bebiocompatible so that the orthopaedic implant 100 is suitable forimplantation at an anatomical site within a patient. It is also usefulif the load bearing member 114 is formed from one or more materials thatare non-resorbable, i.e., the material of the load bearing member 114can maintain at least 90% of its original mass after being implanted ina living patient for at least a year. Examples of such materials arePEEK, tantalum, and titanium, but other porous materials are alsocontemplated as being used. The load bearing member 114 can compriseeither a synthetic material, such as those previously described, or oneor more naturally derived materials, such as a bone graft. The naturallyderived material can also be, for example, cells or tissues harvestedfrom the patient or a different organism, scaffolds created usingcollagen or other biomaterials, etc. It is useful, but not required, forthe load bearing member 114 to substantially fill the cavity 108 so thatat least 90% of the empty space in the implant body 102 defined by thecavity 108 is filled by the bearing member 114. Such filling of thecavity 108 by the load bearing member 114 makes it easier to hold theload bearing member 114 within the cavity 108 during implantation.

The first surface 104 defines a first peak 118, which is a point on thefirst surface 104 that has a maximum height, relative to a groundsurface, when the second surface 106 of the implant body 102 is laid onthe ground surface. The first peak 118 of implant body 102 is best shownin FIG. 28, where it can be seen that the first peak 118 is adjacent tothe first cavity entrance 110. With further reference to FIG. 28, it canbe seen that the first contact surface 116 of the load bearing member114 extends out of the cavity 108 past the first cavity entrance 110 sothat the first contact surface 116 extends past the first peak 118,i.e., the first contact surface 116 is proud of the first surface 104.In this sense, the first contact surface 116 defines a thickness T1 thatextends past and projects from the first surface 104, which can beeither constant or varying throughout the first contact surface 116. Byextending the first contact surface 116 past the first peak 118 of thefirst surface 104, the first contact surface 116 can be placed incontact with an anatomic structure, such as a vertebrae, duringimplantation while isolating the first surface 104 from contact with theanatomic structure. Once implanted, the porous load bearing member 114can then bear load from the anatomic structure while allowing foringrowth of tissue into the load bearing member 114 through the pores117.

Due to the varying shapes of anatomic structures and desired loadbearing characteristics, the first contact surface 116 can be a curvedsurface or a planar surface. The relative sizing between the firstsurface 104 and the first contact surface 116 can also be adjusted, asdesired, to balance the load bearing characteristics of the load bearingmember 114. As can be seen, the first contact surface 116 defines acontact surface area and the first surface 104 defines a first surfacearea, with the contact surface area and first surface area togetherdefining a top surface area of the orthopaedic implant 100. The relativepercentage of the top surface area that the contact surface area makesup can be altered to give varying amount of contact surface for anatomicstructures during implantation. It is contemplated that the contactsurface area can be 40 to 90% of the total surface area when a largecontact surface 116 is desired, or less than 40% of the total surfacearea when a smaller contact surface 116 is desired. It should beunderstood that the term “top surface area” is used for convenience ofdescription only and not to limit the scope of the present invention.

Optionally, the load bearing member 114 can have a second contactsurface 120 extending out of the cavity 108 past the second cavityentrance 112 so that it extends past a second peak 122 of the secondsurface 106 of the implant body 102. The second peak 122 of the secondsurface 106 is analogous to the first peak 118 of the first surface 104,with the key difference being that the second peak 122 defines a maximumheight of the second surface 106 relative to a ground surface when thefirst surface 104 is laid on the ground surface. The second contactsurface 120 can be configured and altered similarly to the first contactsurface 116 so that the second contact surface 120 can be in contactwith an anatomic structure following implantation. The second contactsurface 120 can be a mirror image of the first contact surface 116 or adifferent configuration, depending on the desired load bearingcharacteristics of the load bearing member 114 caused by loads bearingon the first and second contact surfaces 116, 120 from surroundinganatomic structures. It can be useful if the pores 117 of the loadbearing member 114 interconnect from the first contact surface 116 tothe second contact surface 120 so that a travel path through theentirety of the load bearing member 114 can be formed throughinterconnected pores 117 formed therein.

To assist in implanting the orthopaedic implant 100, an opening 124 canbe formed through another surface 126 of the implant body 102 to thecavity 108. The opening 124 can be any size or shape that allows for aninsertion tool (not shown) to be placed within the opening 124 to helpsteady and position the orthopaedic implant 100 during implantation. Theload bearing member 114 can partially extend into the opening 124,another material can be held in the opening 124, or the opening 124 canprovide a clear path to the load bearing member 114 held in the cavity108. In a similar manner, one or more protrusions 128 can be placedadjacent to the opening 124 that are shaped to interact with theinsertion tool and provide a more stable connection between theorthopaedic implant 100 and the insertion tool. The opening 124 andprotrusion(s) 128 can also be configured so that a removal tool (notshown), rather than an insertion tool, can interact with the opening 124and protrusion(s) 128 to remove the orthopaedic implant 100 from apatient following implantation, if necessary.

Referring now to FIGS. 30-31, another embodiment of an orthopaedicimplant 200 is shown that is configured similarly to orthopaedic implant100 previously described. For brevity of description, all features oforthopaedic implant 200 that are analogous to features of orthopaedicimplant 100 are numbered similarly but raised by 100. As can be seen,the first surface 204 of the implant body 202 is covered by an ingrowthmaterial 230, shown as a porous endplate. The ingrowth material 230 cancover all or part of the first surface 204 to encourage ingrowth ofsurrounding tissues into the ingrowth material 230 followingimplantation and provide good integration of the orthopaedic implant200. The ingrowth material 230 can be formed of any material thatencourages ingrowth of a desired body tissue into the ingrowth material230. A non-exhaustive list of contemplated materials includes poroustitanium, tantalum, hydroxyapatite, tricalcium phosphate, PEEK, PAEK,polymethyl methacrylate (PMMA), polylactic acid (PLA), and polyglycolicacid (PGA), but it should be understood that many other types ofmaterials can be used as the ingrowth material 230. Since the loadbearing member 214 will initially bear the brunt of the load fromsurrounding anatomic structures, the ingrowth material 230 can be formedof a lower strength material, with a higher porosity than the loadbearing member 214, or both. For example, the load bearing member 214can be formed of a reinforced PEEK material that has a porosity of 60%and the ingrowth material 230 can be formed of a PEEK material that hasa porosity of 80%. This allows for orthopaedic implant 200 to have ahigher strength material of the load bearing member 214 initially bearthe brunt of the load from surrounding anatomic structures while ahigher porosity material of the ingrowth material 230 allows for bettertissue ingrowth to fixate the orthopaedic implant 200.

As shown in FIG. 31, the ingrowth material 230 has an ingrowth peak 234,which is the highest point of the ingrowth material 230 relative to aground surface when the implant body 202 rests its second surface 206 onthe ground surface. The first contact surface 216 of the load bearingmember 214 extends out of the cavity 208 formed in the implant body 202past the ingrowth peak 234, so that the first contact surface 216 canbear load from an anatomic structure following implantation and isolatethe ingrowth material 230 from initially bearing load from the anatomicstructure. The orthopaedic implant 200 can have a second ingrowthmaterial 236 covering all or part of the second surface 206 of theimplant body 202 and the load bearing member 214 can have a secondcontact surface 220 extending past the second ingrowth material 236similarly to how the first ingrowth material 230 extends past theingrowth peak 234 of the ingrowth material 230. In this sense, theingrowth materials 230, 236 have surfaces that are analogous to thefirst and second surfaces 104, 106 of orthopaedic implant 100 and whichthe load bearing member 214 extends past.

Referring now to FIGS. 32-34, another embodiment of an orthopaedicimplant 300 according to the present invention is shown that includes animplant body 302 configured to be used as a lumbar cage. The implantbody 302 is comprised of a substantially non-porous material and has afirst surface 304; a second surface 306 opposite the first surface 304;a first cavity 308 formed through the first surface 304 and secondsurface 306; and a second cavity 310 formed through the first surface304 and second surface 306. As can be seen, the implant body 302 has aplanar portion 312 that is flat and a curved portion 314 that has asloped curvature. The cavities 308, 310 can be formed through the firstand second surface 304, 306 all or partially within either the planarportion 312 or curved portion 314. A first load bearing member 316 isheld within the first cavity 308 and a second load bearing member 318 isheld within the second cavity 310. The first load bearing member 316 hasa first contact surface 320 and the second load bearing member 318 has athird contact surface 322 that each extend out of their respectivecavity 308, 310 past the plane of the planar portion 312, so that thecontact surfaces 320, 322 can bear load from surrounding anatomicfeatures following implantation. The load bearing members 316, 318 andtheir contact surfaces 320, 322 can be configured similarly topreviously described load bearing members 114, 214, and even though theload bearing members 316, 318 are shown as having different sizes andtotal volumes, their size and total volume could be equal. The contactsurfaces 320, 322 each define a respective thickness T2, T3 relative tothe planar portion 312 of the first surface 304. The thicknesses T2, T3of the contact surfaces 320, 322 can be equal to each other or could bedifferent to provide different load bearing characteristics. Forexample, it may be desirable to provide load bearing member 316 with athicker contact surface 320 than the contact surface 322 of load bearingmember 318 due to the larger overall volume of load bearing member 316,in which case T2 would be greater than T3. It is also contemplated thatthe load bearing members 316 and 318 can be formed of differentmaterials, have differing porosities, or be otherwise configureddifferently from one another to produce a desired healing effect.

Referring now to FIG. 35, the orthopaedic implant 300 shown in FIGS.32-34 is shown with ingrowth material 324 covering the first and secondsurfaces 304, 306 of the implant body 302. The ingrowth material 324 canbe configured in an analogous manner to previously described ingrowthmaterial 230.

Referring now to FIGS. 36-37, another embodiment of an orthopaedicimplant 400 according to the present invention is shown. The orthopaedicimplant 400 includes an implant body 402, configured as an anteriorlumbar interbody fusion cage, comprising a substantially non-porousmaterial having a first surface 404, a second surface 406 opposite thefirst surface 404, and a cavity 408 that extends through the firstsurface 404 and second surface 406. As can be seen, the first surface404 is a sloped planar surface that slopes downward from a front of theimplant body 402 toward a back of the implant body 402. It should beappreciated that the slope of the first surface 404 can be adjusted, asdesired, to provide a variety of shapes for the implant body 402 thatare suitable for different surgical procedures.

A load bearing member 410 comprising a substantially porous material isheld within the cavity 408. The load bearing member 410 has a firstcontact surface 412 that extends out of the cavity 408 and is proud of aportion of the first surface 404 to which the first contact surface 412is immediately adjacent. Put another way, the first contact surface 412outwardly projects from the cavity 408 so that it will contactsurrounding anatomic features when the orthopaedic implant 400 isimplanted and isolate portions of the first surface 404 immediatelyadjacent to the cavity 408 from initially bearing load from thesurrounding anatomic features. Since the first surface 404 is sloped,the first contact surface 412 does not necessarily extend past a peak ofthe first surface 404, as previously described first contact surfacesdo. However, in all other aspects, load bearing member 410 and firstcontact surface 412 can be configured similarly to previously describedload bearing members and contact surfaces.

Referring now to FIG. 38, the orthopaedic implant 400 shown in FIGS.36-37 is shown with an ingrowth material 414 covering the first surface404 of the implant body 402. The ingrowth material 414 can be configuredsimilarly to previously described ingrowth materials. As can be seen,the load bearing member 410 is proud of a portion of the ingrowthmaterial 414 similarly to how the load bearing member 410 shown in FIGS.36-37 is proud of a portion of the first surface 404.

Referring now to FIG. 39, another embodiment of an orthopaedic implant500 according to the present invention is shown. The orthopaedic implant500 includes an implant body 502 formed from a substantially non-porousmaterial having a first surface 504 and a second surface 506 oppositethe first surface 504. The first surface 504 and second surface 506 canbe curved, as shown, or can be formed as planar surfaces that aresubstantially flat. Alternatively, one of the surfaces 504, 506 can beformed as a surface with one or more curvatures while the other surfaceis planar.

A cavity 508 is formed in the implant body 502 extending through thefirst surface 504 and second surface 506 to form a continuous cavity 508through the implant body 502. The cavity 508 has a first cavity entrance510 formed through the first surface 504 and a second cavity entrance512 (FIG. 40) formed through the second surface 506. One or both of thecavity entrances 510, 512 can be concentrically formed through theirrespective surface 504, 506 so that the cavity entrances 510, 512 have aperimeter shape that approximately matches a perimeter shape of theirrespective surface 504, 506, with the cavity entrances 510, 512 having asmaller perimeter than their respective surfaces 504, 506. The cavity508 can be formed to have a constant or varying shape throughout.

A load bearing member 514 comprising a substantially porous materialhaving a first contact surface 516 and having pores 517 is held withinthe cavity 508 that is formed within the implant body 502. The loadbearing member 514 and its contact surface 516 can be configuredsimilarly to previously described load bearing members 114, 214 and 410and their respective contact surfaces 116, 216, and 412.

Preferably, and as illustrated, the first contact surface 516 of theload bearing member 514 extends out of the cavity 508 past the firstcavity entrance 510 so that the first contact surface 516 extends pastthe first surface 504. In this sense, the first contact surface 516defines a thickness T4 that extends past and projects from the firstsurface 504, which can be either constant or varying throughout thefirst contact surface 516. However, in another embodiment, the thicknessT4 has a constant value of zero, thus the first contact surface 516 isflush with the first surface 504. By extending the first contact surface516 past the first surface 504, the first contact surface 516 can beplaced in contact with an anatomic structure, such as a vertebra, duringimplantation while isolating the first surface 504 from contact with theanatomic structure. Once implanted, the porous load bearing member 514can then bear load from the anatomic structure while allowing foringrowth of tissue into the load bearing member 514 through the pores517.

One or more first openings 524 can be formed through another surface 526of the implant body 502 to the cavity 508. The load bearing member 514can partially extend into the first openings 524, another material canbe held in the first openings 524, or the first openings 524 can providea clear path to the load bearing member 514 held in the cavity 508. Thefirst openings 524 can be any size or shape that allows for aninsertion/delivery tool, to be described more fully below, to be placedwithin a first opening 524 (e.g., coupled to the first opening 524) fordelivery of a material agent to the load bearing member 514 via thefirst opening 524 during a surgical procedure for implanting theorthopaedic implant 500. Preferably, the first openings 524 are circularopenings having a threaded outer portion 530 with a diameter d₁, howeverthe scope of the present invention covers first openings 524 having oneor more different diameters or different geometric shapes withassociated geometric parameters (e.g., parameters describing ellipses,squares, rectangles), and may have outer portions 530 that are notthreaded.

Additionally, one or more second openings 528 can be placed adjacent tothe first openings 524, shaped to interact with the insertion/deliverytool (described below) for providing a more stable connection betweenthe orthopaedic implant 500 and the insertion/delivery tool for deliveryof the material agent to the load bearing member 514 via the firstopening 524 and/or for positioning the orthopaedic implant 500 duringimplantation. The first openings 524 and the second openings 528 canalso be configured so that the insertion/delivery tool can interact withthe first opening 524 and the second openings 528 to charge the loadbearing member 514 with a material agent (described more fully below),or to recharge the load bearing member 514 during a second surgicalprocedure, if necessary.

The orthopaedic implant 500 includes plugs 532 that are coupled to thefirst openings 524. The plugs 532 prevent the material agent of the loadbearing member 514, particularly after the load bearing member 514 hasbeen charged with the material agent from the insertion/delivery toolvia the first openings 524, from flowing out of the load bearing member514 via the first openings 524 once the insertion/delivery tool hasfinished charging the load bearing member 514 and/or has been de-coupledfrom the first openings 524.

In another embodiment, the cavity 508 may optionally be divided into twoor more sub-cavities. By way of an exemplary embodiment, the cavity 508may optionally be divided into two sub-cavities 508A and 508B by adivider 509, formed from the same substantially non-porous material ofthe implant body 502. The load bearing member 514 may include porousmaterial of different porosities held within the two sub-cavities 508Aand 508B. In one embodiment, one or more first openings 524 are formedthrough the third surface 526 to each of the sub-cavities 508A and 508B.

FIG. 40 illustrates another view of the orthopaedic implant 500,according to an embodiment of the present invention. Optionally, theload bearing member 514 can have a second contact surface 520 extendingout of the cavity 508 past the second cavity entrance 512 so that itextends past the second surface 506 of the implant body 502. The secondcontact surface 520 can be configured and altered similarly to the firstcontact surface 516 so that the second contact surface 520 can be incontact with an anatomic structure following implantation. The secondcontact surface 520 can be a mirror image of the first contact surface516 or a different configuration, depending on the desired load bearingcharacteristics of the load bearing member 514 caused by loads bearingon the first and second contact surfaces 516, 520 from surroundinganatomic structures. It can be useful if the pores 517 of the loadbearing member 514 interconnect from the first contact surface 516 tothe second contact surface 520 so that a travel path through theentirety of the load bearing member 514 can be formed throughinterconnected pores 517 formed therein.

As illustrated, the second contact surface 520 defines a thickness T5that extends past and projects from the second surface 506, which can beeither constant or varying throughout the second contact surface 506.However, in another embodiment, the thickness T5 has a constant value ofzero, thus the second contact surface 520 is flush with the secondsurface 506.

FIG. 41 illustrates a cross-sectional view of the orthopaedic implant500, with the plug 532 removed, according to an embodiment of thepresent invention. For ease of illustration, only one first opening 524is shown. The first opening 524 includes the threaded outer portion 530and an inner portion 534, which is preferably threaded, however thescope of the invention covers the inner portion 534 being non-threaded,and having instead notches replacing the threads, or other means ofremovably-coupling a plug (shown in FIG. 42). The threaded outer portion530 has an outer diameter d_(o) and the threaded inner portion 534 hasan inner diameter d₁. In one embodiment, the inner diameter d_(i) isless than the outer diameter d_(o). Reference numbers that are the sameas the reference numbers of the previous figures refer to the samefeatures.

FIG. 42 illustrates the plug 532, according to an embodiment of thepresent invention. The plug 532 includes a threaded proximal portion536, a distal portion 538, and a middle portion 540 positioned betweenthe threaded proximal portion 536 and the distal portion 538. Thethreaded proximal portion 536 is configured to be coupled (e.g.,threaded) with the threaded inner portion 534 of the first opening 524.However, the scope of the present invention covers other means ofremovably-coupling a proximal portion 536 of the plug 532, in which theproximal portion 536 has, for example, ridges for removably-couplingwith, for example, notches of the inner portion 534. The middle portion540 has a diameter d_(m) and the distal portion 538 has a diameterd_(d). The distal portion 538 has a distal end 542, preferably shapedfor receiving a rotating means, such as a socket (not shown), forexample. Although in the embodiment as illustrated, the distal end 542is shaped as a hexagon, the scope of the present invention covers thedistal end 542 formed in any shape (e.g., shaped as a cylindercontaining a socket for receiving a corresponding rotating means). Inone embodiment, the diameter d_(m) of the middle portion 540 is lessthan or equal to the diameter d_(o) of the threaded outer portion 530 ofthe first opening 524 and greater than the diameter d_(i) of thethreaded inner portion 534 of the first opening 524, and the diameterd_(d) of the distal portion 538 is less than the diameter d_(o) of thethreaded outer portion 530 of the first opening 524 for accommodating arotating means within the threaded outer portion 530 of the firstopening 524 for threading the plug 532 into the inner portion 534 of thefirst opening 524 and de-threading (i.e., removing or decoupling) theplug 532 from the inner portion 534 of the first opening 524.

FIG. 43 illustrates a cross-sectional view of the orthopaedic implant500, including the plug 532 coupled to the first opening 524 for sealingthe first opening 524, according to an embodiment of the presentinvention. For ease of illustration, only one first opening 524 isshown. As illustrated, the diameters d_(m) and d_(d). (shown in FIG. 42)of the middle and distal portions 540, 538, respectively, of the plug532, are less than the diameter d_(o) (shown in FIG. 41) of the threadedouter portion 530 of the first opening 524. In one embodiment, once theplug 532 is coupled in place within the first opening 524, viaapplication of a rotating means (not shown), the middle portion 540 ofthe plug 532 may abut against a wall 544 separating the threaded outerportion 530 of the first opening 524 from the threaded inner portion 534of the first opening 524. Although the coupling of the threaded proximalportion 536 with the threaded inner portion 534 of the first opening 524may adequately seal the first opening 524 of the implant 500 fromleaking a material agent contained within the load bearing member 514,the abutment of the middle portion 540 of the plug 532 against the wall544 may assist in sealing the first opening 524, as well as preventingthe plug 532 from being threaded too far into the first opening 524. Inaddition, as seen further below in conjunction with FIG. 44, the middleportion 540 may provide a means for a plunger 606 of aninsertion/delivery tool 600 to slide the plug 532 in a cannula 604 ofthe insertion/delivery tool to position the plug 532 adjacent to thethreaded inner portion 534, such that the plug 532 may subsequently becoupled to the threaded inner portion 534 via a rotating means, asdescribed more fully further below.

FIG. 44 illustrates a cross-sectional view of the insertion/delivery(ID) tool 600 coupled to the orthopaedic implant 500 illustrated inFIGS. 39-41 and FIG. 43, according to an embodiment of the presentinvention. The insertion delivery tool 600 is shown coupled to theorthopaedic implant 500 for ease of description. FIG. 45 illustratesseveral components of the ID tool 600, when the ID tool 600 is decoupledfrom the orthopaedic implant 500, according to an embodiment of thepresent invention. Reference is made to both FIGS. 44 and 45 in thefollowing description.

The ID tool 600 includes an inserter 602, a cannula 604 (i.e., a tube),and a plunger 606. In one embodiment, the inserter 602 includes atubular portion 608, an attachment portion 610 positioned at a first end611 of the tubular portion 608, and a handle portion 612 positionedaround a second end 613 of the tubular portion 608. The attachmentportion 610 may include one or more pins 614 configured to engage with(also referred to as couple with or interact with) the one or moresecond openings 528 for enabling the inserter 602 to insert and/orposition the orthopaedic implant 500 during implant, and/or stabilizethe orthopaedic implant 500 for delivery of a material agent 619 to theorthopaedic implant 500 via the first openings 524, as will be describedshortly. In addition, the attachment portion 610, including the one ormore pins 614 engaged with the one or more second openings 528, incombination with the tubular portion 608, provides a means for guidingthe cannula 604 to the first opening 524 and stabilizing the orthopaedicimplant 500 when the cannula 604 is for coupled to the first opening524.

The cannula 604 includes a tubular passage 605 having an attachmentportion 616 configured to be coupled to the orthopaedic implant 500. Inone embodiment, the attachment portion 616 is threaded. The threadedattachment portion 616 is configured to thread with the outer threadedportion 530 of the first opening 524. However, the scope of theinvention covers the attachment portion 616 being non-threaded, havinginstead other means of attachment for attaching to the outer portion 530of the first opening 524. The cannula 604 also includes a receiving end618 configured to receive the material agent 619 and the plug 532coupled to a the plunger 606. The receiving end 618 may also beconfigured to receive a rotatable means (not shown) for rotating thecannula 604 for threading the threaded attachment end 616 with thethreaded outer portion 530 of the first opening 524 for securely, butremovably, coupling the cannula 604 to the orthopaedic implant body 500(e.g., to the first opening 524). As illustrated, the inserter 602 andthe cannula 604 are configured such that the cannula 604 may bepositioned in the tubular portion 608 of the inserter 602 (i.e., slidinside the tubular portion 608 of the inserter 602) for coupling thecannula 604 to the orthopaedic implant 500 via the threaded outerportion 530 of the first opening 524.

The insertion/delivery tool 600 also comprises the plunger 606. Theplunger 606 includes a first end 620 and a handle end 622, connected toeach other via a rod 624. The first end 620 is configured to couple withthe distal portion 538 of the plug 532 for pushing the plug 532, and thematerial agent 619 residing in the cannula 604 between the plug 532 andthe attachment end 616, through the cannula 604 towards the firstopening 524. In one embodiment, the first end 620 is a hexagon-shapedsocket configured to couple with a hexagon-shaped distal end 542 of theplug 532. Once the first end 620 of the plunger 606 is coupled with thedistal end 542 of the plug 532, a force may be applied to the handle end622 for pushing the plug 532 (and any material agent 619 residing in thecannula 604 between the plug 532 and the attachment end 616) through thecannula 604, thereby forcing the material agent 619 into the loadbearing member 514 via the first opening 524, and once the threadedproximal portion 536 of the plug 532 is pushed up against the threadedinner portion 534 of the first opening 524, the handle end 622 may berotated for threading the plug 532 into the threaded inner portion 534of the first opening 524, thereby sealing the first opening 524 againstexpulsion or leakage of the material agent 619 from the load bearingmember 514. In one embodiment, the plunger 606 comprises one or moresealing rings 624, such as O-rings, positioned around the rod 624 forpreventing leakage of the material agent 619 into a portion of thecannula 604 between the sealing ring 624 and the receiving end 618 ofthe cannula 604 as the plunger 606 is being pushed down the cannula 604in the direction of the first opening 524.

In one embodiment, and as illustrated, the tubular passage 605 has atubular passage diameter d_(p), and the middle diameter d_(m) of theplug 532 is equal to the tubular passage diameter d_(p) and the distaldiameter da of the plug 532 is less than the tubular passage diameterd_(p).

In another embodiment, the inserter 602 and the cannula 604 positionedwithin the tubular portion 608 of the inserter 602 may collectively bereferred to as a tubular assembly 603 having the tubular passage 605.The tubular assembly also includes a first end 607 configured to couple(i.e., attach) to the orthopaedic implant 500 and a second end 609configured to receive the material agent 619, the plug 532 and theplunger 606.

FIG. 46 illustrates the first end 620 of the plunger 606, according toanother embodiment of the present invention. In this embodiment, thefirst end 620 is connected to the distal end 542 of the plug 532 at ajoint 626, or in other words, the first end 620 includes the plug 532.In operation, once the inserter 602 and the cannula 604 have beencoupled to the orthopaedic implant 500, and the material agent is placedin the receiving end 618 of the cannula 604, and the plunger 606,including the first end 620 connected to the plug 532, has pushed thethreaded proximal portion 536 up against the threaded inner portion 534of the first opening 524, the plunger 606 is rotated, causing the plugto be threaded into the threaded inner portion 534. In one embodiment,the first end 620 is connected to the distal end 542 of the plug 532 insuch a manner that once the threading of the plug is complete, therebysealing the first opening 524, any further rotation of the plunger 606causes the first end 620 to break with the distal end 542 of the plug532 along the joint 626, allowing removal of the plunger 606 from thecannula 604. In one embodiment, the distal end 542 is configured as ahexagon, or any other shape, to allow the plug 532 to be de-threaded(i.e., removed) from the first opening 524 at a later time. In anotherembodiment, the distal end 542 is not configured to accommodate anyrotational means for removing the plug 532, and thus the plug 532 ispermanently coupled to the first opening 524.

FIG. 47 shows method steps for charging of the orthopaedic implant 500with the material agent 619.

In step 628, the inserter 602 is coupled to the orthopaedic implant 500.In one embodiment, the one or more pins 614 of the attachment portion610 of the inserter 602 is coupled to the one or more second openings528 of the orthopaedic implant 500. In one embodiment, the two secondopenings 528 are formed in the surface 526, also referred to as a sidesurface of the orthopaedic implant. The surface 526 is formed betweenthe first surface 504 and the second surface 506 of the orthopaedicimplant 500. In an embodiment, the two second openings are formed tostraddle the first opening 524 in the surface 526.

In step 630, the cannula 604 is coupled to the orthopaedic implant 500.In one embodiment, the attachment portion 616 of the cannula 604 is slidinto the inserter 602 until the attachment portion 616 reaches the outerportion 530 of the first opening 524. The cannula 604 is then rotated,preferably via use of a rotating means, such as a socket, wrench, etc.,applied to the receiving end 618 of the cannula 604, causing theattachment portion 616 to rotate, thereby coupling the attachmentportion 616 to the outer portion 530 of the first opening 524. In oneembodiment, the both the attachment portion 616 and the outer portion530 are threaded, and the rotation of the cannula 604 causes thethreaded attachment portion 616 to thread with the threaded outerportion 530, thereby coupling the cannula 604 to the orthopaedic implant500, or according to one embodiment, to the first opening 524 of theorthopaedic implant 500.

In step 632, the material agent 619 is placed into the cannula 604 viathe receiving end 618. In one embodiment, the material agent is aflowable material. The scope of the present invention covers flowablematerials, such as bone pastes, bone putties, bone grafts, ortherapeutics, for example, antibiotics, blood plasmas, bone marrow, painmedications, or drugs, such as tumor-fighting drugs, all havingconventional viscosities known to those of skill in the art.Furthermore, the scope of the present invention covers any biologicalmaterial agents that may be embodied as a flowable material. Inaddition, the scope of the present invention covers material agentshaving a range of viscosities, which in combination with a porous loadbearing member 514 having various interconnectivities and pore sizes,are deliverable into the porous load bearing member 514 via the firstopening 524, the cannula 604 and the plunger 606.

In step 634, the first end 620 of the plunger 606 coupled to the plug532 is inserted into and pushed through the cannula 604 in the directionof the first opening 524, thereby enabling the plug 532 to push thematerial agent 619 in the direction of the first opening 524 and forcingthe material agent 619 through the first opening 524 for charging theporous load bearing member 514 of the orthopaedic implant 500 with thematerial agent 619. In one embodiment, the first end 620 of the plunger606 is removeably-coupled to the distal end 542 of the plug 532, via forexample, a socket. In another embodiment, the first end 620 of theplunger 606 is breakably-coupled to the distal end 542 of the plug 532at a joint 626 between the distal portion 542 and the first end 620.

In step 636, after the plunger 606 coupled to the plug 532 has pushedthe proximal portion 536 of the plug 532 adjacent to the inner portion534 of the first opening 524, the plunger 606 is rotated within thecannula 604, causing the plug 532 to couple (also referred to as attachor fasten) with the first opening 524, thereby sealing the first opening524. In one embodiment, both the proximal portion 536 of the plug 532and the inner portion 534 of the first opening 524 are threaded, and therotation of the cannula 604 causes the proximal portion 536 to threadwith the inner portion 534, thereby sealing the first opening 524against expulsion (also referred to as leakage) of the material agent619 of the load bearing member 514 through the first opening 524.

In step 638, if the first end 620 of the plunger 606 isremovably-coupled to the distal end 542 of the plug 532, then after theplug 532 is threaded into the first opening 524 in step 636, the firstend 620 of the plunger 606 is decoupled from the distal end 542 and theplunger 606 may be removed from the cannula 604. If the first end 620 ofthe plunger 606 is breakably-coupled to the distal end 542 of the plug532 at the joint 626, then after the plug 532 is threaded into the firstopening 524 in step 636, further rotation of the plunger 606 causes thefirst end 620 to break with the distal end 542 of the plug 532 along thejoint 626. The plunger 606 may then be removed from the cannula 604.

In step 640, the cannula 604 is rotated within the inserter 602 in theopposite direction as in step 630, thereby de-coupling the cannula 602from the orthopaedic implant 500. For example, rotating the cannula 604in the opposite direction unthreads the threaded attachment end 616 ofthe cannula 604 from the threaded outer portion 530 of the first opening524, thereby allowing the cannula 604 to be slid out of the tubularportion 608 of the inserter 602.

In step 642, the inserter 602 is de-coupled from the orthopaedic implant500. In one embodiment, the one or more pins 614 of the attachmentportion 610 of the inserter 602 is de-coupled from the one or moresecond openings 528 of the orthopaedic implant 500.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

What is claimed is:
 1. A method of charging an orthopaedic implant witha material agent, said orthopaedic implant including an implant bodyhaving a first surface, a second surface opposite said first surface, acavity formed therein that extends through said first surface and saidsecond surface, said implant body being substantially non-porous, saidimplant body further including a third surface with at least one firstopening formed therethrough to said cavity and at least one secondopening, said at least one first opening comprising an threaded outerportion having an outer diameter and an threaded inner portion having aninner diameter, said outer diameter greater than said inner diameter,and a load bearing member comprising a substantially porous materialheld within said cavity, said load bearing member configured to receive,via said at least one first opening, said material agent, said loadbearing member having a first contact surface extending out of saidcavity past said first surface, said method comprising: coupling atubular assembly to said third surface of said implant body, whereinsaid tubular assembly includes a tubular passage having a first end anda second end, and wherein said first end is coupled to said thirdsurface such that said tubular passage is centered on said at least onefirst opening; placing said material agent into said tubular passage viasaid second end; sliding a plunger coupled to a plug through saidtubular passage via said second end, thereby expelling said materialagent from said tubular passage into said load bearing member via saidat least one first opening; and rotating said plunger within saidtubular passage for coupling said plug with said at least one firstopening for sealing said at least one first opening against expulsion ofsaid material agent from said load bearing member via said firstopening.
 2. The method of charging an orthopaedic implant according toclaim 1, wherein said tubular assembly comprises an inserter and acannula, wherein said inserter includes a tubular portion and anattachment portion having at least one pin, wherein said cannulaincludes a threaded attachment portion, and wherein coupling saidtubular assembly to said third surface of said implant body furthercomprises: coupling said at least one pin of said inserter to said atleast one second opening of said third surface of said implant body;sliding said cannula into said tubular portion of said inserter; andcoupling said threaded attachment portion of said cannula to saidthreaded outer portion of said at least one first opening of said thirdsurface, wherein said cannula includes said tubular passage.
 3. Themethod of charging an orthopaedic implant according to claim 2, furthercomprising: decoupling said plug from said plunger; withdrawing saidplunger from said tubular passage via said second end; decoupling saidcannula from said threaded outer portion of said at least one firstopening of said third surface; withdrawing said cannula from saidtubular portion of said inserter; and decoupling said inserter from saidat least one second opening of said third surface of said implant body.4. The method of charging an orthopaedic implant according to claim 3,wherein if said plunger is coupled to said plug via a breakable joint,said decoupling said plug from said plunger comprises rotating saidplunger within said tubular passage until said breakable joint breaks.5. The method of charging an orthopaedic implant according to claim 1,wherein said material agent is a flowable material.
 6. The method ofcharging an orthopaedic implant according to claim 5, wherein saidflowable material is a bone graft.
 7. The method of charging anorthopaedic implant according to claim 5, wherein said flowable materialis a bone putty.
 8. The method of charging an orthopaedic implantaccording to claim 5, wherein said flowable material is a therapeutic.